This invention relates to turbomachinery and specifically to the winding of generator stators.
During the process of winding a generator stator (such as shown in U.S. Pat. No. 4,572,980, the disclosure of which is hereby incorporated by reference), there is a need at several points in the process to apply radial pressure to the armature winding elements, commonly referred to as armature bars, to firmly force the bars and other slot contents against the bottom of the stator core slot. The conventional device for applying the pressure is an expandable strut containing a hydraulic ram with jacking boards at both ends for distributing the applied force. The strut is positioned radially across the inside diameter of the stator core and the jacking boards are placed within two diametrically opposite slots. The hydraulic ram is pumped to a known pressure resulting in a pressure applied to the armature bar areas contacted by the jacking boards. The bar-jacking device is heavy, bulky, and cumbersome to use. Two operators are needed to set up and use the device. During use of the conventional device, access to the bore of the stator core is restricted due to the size and span of the device. The conventional device also holds the potential for leakage of the hydraulic fluid and contamination of the stator core and armature winding.
According to the present invention a turbine generator armature bar pressure applicator, a turbine generator stator assembly, and a method of mounting armature bars in a turbine generator stator, are provided which are simple and easy to use. The applicator according to the invention is compact, hand-held, and lightweight (and hence portable), so that it can be used by a single operator during conventional winding or rewedging processes. The device also has no potential for contaminating the stator core and armature winding, or any accessory structures.
According to one aspect of the present invention there is provided a turbine generator armature bar pressure applicator, comprising: A retainer platform having first and second portions mounted to slide with respect to each other to adjust the operative width of the platform, and configured to slide in a dovetail slot in a stator for receipt of armature bars, the platform having a top surface. An inflatable bladder operatively associated with [for example mounted to, resting on, or in any other way associated with so that the desired functionality is provided] the top surface and dimensioned so as to apply radial pressure to armature bars mounted in a stator. And, a conduit extending from the inflatable bladder for supplying gas under pressure to the bladder to selectively inflate the bladder.
The applicator preferably further comprises a valve operatively connected to the conduit for selectively allowing pressurized gas to pass through the conduit into the bladder, or for venting pressurized gas from the bladder; preferably the valve may be a conventional valve that has a quick-release function, so that the bladder may be vented quickly. The inflatable bladder may comprise a wide variety of different structures such as a flexible wall hose.
Typically the applicator further comprises at least one handle mounted to the platform opposite the top surface. Desirably the platform is dimensioned and constructed so as to be readily handled by a single person (e.g. a normal adult male). The platform typically comprises first and second portions that are generally wedge-shaped, and the at least one handle comprises first and second handles each substantially centrally located in first and second portions, respectively.
According to another aspect of the present invention a turbine generator stator assembly is provided, comprising: A turbine generator stator having a plurality of generally radially extending slots each with an access opening, and a dovetail slot in the stator adjacent the openings and extending generally perpendicular to the radial slots. A plurality of armature bars are inserted in at least one of the radial slots. An inflatable bladder operatively engaging the armature bar, the bladder operatively connectable to a source of gas under pressure. A hand held platform mounting the bladder and slidable in the dovetail slot. And, the bladder provided with gas under pressure to expand and apply radial pressure to the armature bars to press the armature bars into the radial slot, and the bladder vented to release gas under pressure from the bladder.
Typically there is at least one filler between the bladder and the armature bars. The bladder is typically operatively connected to a source of gas under pressure by a conduit, and the assembly further comprises a valve operatively connected to the conduit for selectively allowing pressurized gas to pass through the conduit into the bladder, or for venting pressurized gas from the bladder. The valve preferably comprises a quick-release valve. Typically there is at least one handle mounted to the platform opposite the top surface, and the inflatable bladder may comprise a flexible wall hose.
According to another aspect of the present invention there is provided a method of mounting armature bars in a turbine generator stator having a plurality of generally radially extending slots each with an access opening, and a dovetail slot in the stator adjacent the openings and extending generally along the radial slots, and using an inflatable bladder on a hand held platform, the method comprising, substantially sequentially: (a) Inserting an armature bar in one of the radial slots through the access opening. (b) Moving the inflatable bladder into operative engagement with the armature bars, including by moving the platform in the dovetail slot. (c) Supplying gas under pressure to the bladder to expand the bladder and apply radial pressure to the armature bars to press the armature bars into the radial slot through the access opening. (d) Venting gas under pressure from the bladder so that the bladder is no longer in operative engagement with the armature bar.
Preferably the platform comprises first and second wedge-shaped portions slidable with respect to each other to adjust the effective width thereof and each portion having at least one handle; and in the method preferably (b) is practiced by manually moving the portions with respect to each other by engaging the handles so that the platform is of a width that will slide in the dovetail slot until the bladder is aligned with the armature bar; and then manually moving the handles with respect to each other to cause the platform to have a width that causes the platform to be substantially wedged in a stationary position in the dovetail slot. The method also preferably further comprises, between (a) and (c), inserting at least one filler between the bladder and the armature bar. Desirably the inflatable bladder has a quick-release valve operatively associated therewith, and (d) is practiced by manually actuating the quick-release valve. In the method, (c) may be practiced to supply gas under a pressure of about 80-120 (e.g. about 100) psi to the inflatable bladder.